Battery Venting Coupling for Shock Wave and Turbulence Damping
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Solution Overview
Problem
Aircraft battery venting systems face issues with shock waves and turbulence due to high-pressure gas emissions, leading to increased weight and fuel consumption in the venting system, as existing solutions like burst discs and bellows-type expansion joints cause complex shock patterns and flow losses.
Innovation Solution
A venting device comprising a burst disc, fluid flow path with outlet ducts, a flexible coupling around the junction, and a piston seal, which absorbs shock waves by allowing relative sliding movement and forming an expansion cavity for gases, reducing turbulence and weight requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a burst disc is used as a pressure relief safety valve, then pressure relief function is provided, but shock waves are generated causing turbulence and flow losses
Solution Approach 1:
A bellows-type expansion joint is introduced as an intermediary component between the burst disc and the venting system. This expansion joint absorbs the shock waves generated by the burst disc through its flexible corrugated structure, preventing the shock waves from propagating through the venting system while maintaining the pressure relief function.
Solution Approach 2:
The venting system incorporates a variable cross-sectional area design in the outlet ducts, creating expansion and contraction sections that modify the flow parameters. This gradual area change reduces the intensity of shock waves and minimizes turbulence by controlling the expansion of gases as they exit the burst disc.
2Strength
If the venting system is made very strong to withstand excess pressure, then pressure resistance is improved, but weight increases leading to increased fuel consumption
Solution Approach 1:
The venting system utilizes a bellows-type expansion joint with flexible corrugated walls instead of rigid thick-walled structures. This flexible shell design provides sufficient pressure resistance through its structural geometry and material properties while maintaining thin walls, thereby reducing the overall weight of the venting system.
Solution Approach 2:
The venting system incorporates movable and flexible components such as the bellows expansion joint that can dynamically deform under pressure loads. This dynamic design allows the system to withstand excess pressure through elastic deformation rather than requiring over-engineered static strength, reducing material usage and weight.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively dampens shock waves and reduces turbulence in the fluid flow, allowing for lighter and more efficient venting systems that minimize strain and fuel consumption, while maintaining structural integrity and reducing noise and vibration.
Implementation Method 1
The provision of a flexible coupling allows for shock waves to be absorbed or dampened
Implementation Method 2
The flexible coupling may include first and second rigid structural members associated with the respective outlet ducts and a flexible sleeve between the rigid structural members
Implementation Method 3
The piston seal and the flexible coupling may be arranged to provide an expansion cavity for gases exiting the burst disc. Shock waves produced by the gases interact with the flexible coupling by means of the expansion cavity
Implementation Method 4
The burst disc is arranged to rupture when the pressure inside a battery module increases beyond a predetermined threshold
Data Source
AI summary
A venting device 9a to 9c for a battery 6a including a burst disc 13; a fluid flow path including first and second outlet ducts 14, 15; a flexible coupling 16 around a junction between the first and second outlet ducts; and a piston seal 17 between one of the outlet ducts and the flexible coupling. The piston seal 17 and the flexible coupling 16 provide an expansion cavity 22 for gases exiting the burst disc. The flexible coupling 16 includes an elastomeric tube 20 arranged to expand as the device reacts to a shock wave and returns to normal dimensions.